What is it that makes an exhibition special, keeps you looking longer than you expected, ensures you think about it long after you’ve left? Obviously, the art, or in a history show, the subject, is the first thing. The installation sometimes (although a good show is more usually damaged by poor installation than a poor one is rescued by good). Then there are the juxtapositions, the unexpected nuggets of information, novelty, rarity.

Who would have thought that in a comic opera by Donizetti, least orchestra-indulgent of Italian composers, the conductor could be paramount?

Dogs, horses, cows, sheep, goats and pigs are the creatures that, however minuscule in stature, take pride of place in the fascinating exhibition of Thomas Gainsborough’s imaginary landscapes at the Holburne in Bath, an ideal complement to the nine major Gainsborough portraits in their British picture gallery.

Surprisingly for one of the most prominent portrait-painters in all of British art, Gainsborough's animals, lovingly portrayed, their body language based on acute observation, dominate their human counterparts in these landscapes, who are more or less rural stereotypes.

It’s not every evening one is invited to take A Dish of Tea with Dr Johnson, and the 90 minutes spent in the company of England’s greatest wit and original lexicographer pass in a whirl of aphorisms and expostulations, with a fair smattering of historical grandees thrown in for good measure. That this production is a two-hander is no impediment to appearances from Joshua Reynolds, Flora MacDonald, the Prince Regent and Oliver Goldsmith (“He goes on without knowing how he is to get off”), not forgetting Johnson’s beloved cat Hodge.

Over the past six weeks of the Proms the BBC’s hard-working Symphony Orchestra has performed everything from Britten to Brahms, Verdi to Volans. Their Mahler with Ed Gardner was an operatic epic, their programme of English music for Mark Wigglesworth glowed with wit. Yet hearing their ragged and unlovely account of Beethoven’s Ninth Symphony last night it was hard to remember their triumphs, hard even to remember the delicate account of Graham Fitkin’s new Cello Concerto that they delivered in the first half, so complete was their collapse.

A legendary septuagenarian wind player from Switzerland returns to the repertoire with which he made his name 50 years ago, and there's an exciting live reading of a gloomy fin-de-siècle symphony conducted by a contemporary French giant. The same conductor also treats us to a sparkling Stravinsky rarity, and a youthful duo lighten the mood with some Russian fireworks on Merseyside.

Never has a French invasion of these shores been quite so welcome. The two-day siege currently being staged in the Royal Albert Hall by Myung-Whun Chung and his Orchestra Philharmonique de Radio France opened last night with patriotic fervour in an all-French programme. Even Beethoven’s Triple Concerto began rolling its “R”s when cajoled into life by the dashing Capuçon brothers. While their strongly accented interpretation may not have been to everyone’s taste, as an exhalation after the meditative intensity of Messiaen and Dusapin it was perfectly judged.

Gleaming, shimmering, full of pizzazz, glitz and unashamed bling, although of the 18th-century sort, as befits its role as the most cheerfully mixed up and glittering show of baubles in Bath, the Holburne Museum reopened in May after three years' closure. At a cost of £11.2 million the museum has been expanded, rebuilt, refurbished and renovated. Much more of the collection, newly installed after extensive conservation, is also on view than hitherto. The whole works a treat. As many visitors have turned up in the first month as normally come in a year.

John Gay’s 1728 satirical drama was the first ballad opera. The vernacular work not only cocked a snook at the Italian operas that were so in vogue in 18th-century London, but it also lampooned Whig politician Sir Robert Walpole and the British love for scoundrels. It was an instant, huge hit; as a witticism of the time had it, The Beggar’s Opera made Rich gay, and Gay rich.

While we are far from lacking in top early music ensembles in the UK, there’s no denying that the French have a special affinity for this repertoire. While The Academy of Ancient Music and The Orchestra of the Age of Enlightenment are virtuosic champions of the genre, if we were all stuck in a sinking hot air balloon I’d lose both before sacrificing Les Musiciens du Louvre, Les Talens Lyriques, Le Concert d'Astrée or Les Arts Florissants. So it was with anticipation that I made my way to the Barbican last night to hear the UK debut of Le Cercle de l’Harmonie, the newest French orchestra on the block.