When Lahti’s Sibelius Hall finally shone and coruscated into life in 2000, the 100,000 citizens of this modest Finnish town, not to mention acousticians from all over the world, could hardly believe their eyes and ears. Here, at last, was not only a top concert hall fit for what had already become a world-class orchestra under notable Sibelian Osmo Vänskä, but also a twofold architectural wonder.

Last night's Proms performance of Sibelius's Kullervo symphony was radiant, unforgettable, but there has also been a pure coincidence this past week which is simply too good to pass over unremarked: Thursday also saw the first-time publication of J.R.R. Tolkien's version of the same narrative, The Story of Kullervo.

It’s been glorious to hear so much Bach at this year’s Proms – most of it after dark, and still more of it for the most intimate of forces. On paper, the Academy of Ancient Music and BBC Singers’ Late Night concert of Bach choral works didn’t quite have the mystique of Ibragimova’s Solo Sonatas and Partitas, Schiff’s Goldbergs or Ma’s Cello Suites. In practice, though, it was clever piece of programming that came into its own in its Friday night slot, sending people home to the weekend on the very highest of musical highs.

Nearly 10 years ago to the day, an almost unknown 24-year-old Venezuelan conductor came a cropper when valiantly stepping in at short notice to conduct Sibelius’s Fifth Symphony at the Proms. (His name was Gustavo Dudamel. Whatever happened to him?) To pull off successful performances of Sibelius’s seven symphonies you need not just the ability to fire up players but the intellectual grasp to grip their elusive, fluid structures.

A second night of Sibelius symphonies at the Proms, packed to the rafters just like its predecessor. Exit Thomas Dausgaard, the tuba needed for the first two symphonies but not for the Third or – surprising given its pervasive darkness – the Fourth, and the air that had billowed around supremely supple performances. Enter Ilan Volkov to bring too much dark earth and inorganic point-making at first, though the BBC Scottish Symphony Orchestra, its strings sounding tougher if less inward from a different point in the hall, was still on world-class form.

From Sakari Oramo’s riveting Nielsen symphonies at the Barbican to Thomas Dausgaard kicking off the Proms’ Sibelius cycle, the two Nordic immortals are well served in their 150th birthday year. The BBC Scottish Symphony Orchestra, whose reins Dausgaard takes over from the great Donald Runnicles in 2016, may not have the sheer heft of the Berlin Philharmonic strings we heard earlier this year in Rattle’s Sibelius. But the Glasgow-based players get much deeper under the skin, and prove so much lighter on their feet when the Danish conductor takes flight.

In his memoir As I Remember Arthur Bliss is reticent about his experiences on the Western Front. He describes his “purely automatic” impulse to enlist in August 1914, and later recounts the nightmares that troubled his sleep for a decade after the Armistice. He barely touches upon the injury that felled him on the first day of the Somme, the experience of being gassed late in 1918, or indeed the death in battle of his beloved younger brother Kennard – describing an unending sense of loss in a single paragraph.

So it begins. Thousands of expectant audience members in a sweltering Albert Hall – heave ho! – riotous applause for the leader as he tunes the orchestra. A few more visits and all this will seem normal again, but it’s a culture shock to be thrown straight back in on the first night.

Medtner: Piano Sonatas Alessandro Taverna (Somm)

Vladimir Ashkenazy should be made an honorary Finn: not just for his constant championship of Sibelius’s orchestral works throughout his conducting life so far, but above all for the way he understands them. On the evidence of last night’s 150th anniversary concert, crowned by a superbly direct performance of the Second Symphony, his approach is now thoroughly Finnish at the deepest level in the way that it paces the sentiment, effortlessly negotiates the shifts of mood without histrionics and shears the music of romantic rhetoric. No Slavic or Teutonic plushness here.