One miracle of musical performance is that a work you’ve loved for years can be revealed as never before in an outstanding interpretation. That happened to me last week at the New Ross Piano Festival when 22-year-old pianist Magdalene Cho turned us upside down in Bach’s Sixth Partita. It happened again last night when Peter Whelan and his Irish Baroque Orchestra hit 1788 with one of the three symphonic masterpieces Mozart composed in a single summer, the 39th.

The revival of Robert Carsen’s production of Handel’s Ariodante at the Opéra Garnier in Paris under the direction of Raphaël Pichon, with his Ensemble Pygmalion and a top-notch cast, is well worth a trip to Paris. At over four hours, it might seem daunting, but the show is as close to perfection as opera can be, bursting with vitality and emotion, and never feels a second too long.

35 years ago, persona-now-non-grata John Eliot Gardiner revealed how performances of Mozart’s Idomeneo and La Clemenza di Tito allying period instruments with great voices could electrify in a new way. And here we were last night with Pablo Heras-Casado, a conductor as at home in Wagner at Bayreuth as he clearly is with the Monteverdi Choir and Orchestre Révolutionnaire et Romantique, stunning us with a consistently vigilant and alive Mozart Requiem.

Manchester Camerata is enhancing its reputation for pioneering with three performances featuring Nick Martin’s new Violin Concerto, which it has commissioned, two of them in art galleries rather than conventional music venues.

The Buxton International Festival this year was lavish in its smaller-scale productions in addition to Ambroise Thomas’s Hamlet, the heavyweight offer of the opera programme. And outstanding among them was the combination of Bernstein’s Trouble in Tahiti and Poulenc’s La Voix Humaine: seen by director Daisy Evans not just as a double bill with an overlapping need for telephones on set, but as two sides of the same story.

Poor, slightly silly Semele fries at the sight of lover Jupiter casting off his mortal form, but in Congreve’s and Handel’s supposedly happy ending, everyone else rejoices that Bacchus is the offspring of this dalliance. Or do they? Not in the new production by Royal Opera supremo Oliver Mears, who’s always favoured the dark side. As in trendy dramas like TV’s Kaos, the gods are the callous rich, mortals their plaything servants.

Over 100 years ago, John Christie envisaged Wagner’s Parsifal with limited forces in the Organ Room at Glyndebourne. He would have been amazed to see it arrive on the main stage this year. But émigrés Carl Ebert and Fritz Busch persuaded him that Mozart was the real country-house ideal. Le nozze di Figaro remains Glyndebourne’s perfect opera, and Mariame Clément’s new production, launched last night with the 588th performance here, keeps it real.

Tchaikovsky has precisely two operas in the standard repertoire (including The Queen of Spades, currently playing at Garsington), and readers who love those works might well be forgiven for wondering what happened to the other eight or nine. On the evidence of Grange Park’s Mazeppa, the answer might seem to be pure mischance.

The opening images of Tornado are striking. A wild-haired young woman in Japanese peasant garb runs for her life through a barren forest and across burnt-orange fields. As her pursuers, a rough-looking band of thieves, draw nearer, she seeks refuge in a seemingly deserted mansion. Where are we? When are we?