Mahler said of the last movement of his Fourth Symphony that it should be pure, like the “undifferentiated blue of the sky”. Writing the symphony in his lakeside retreat at Maiernigg in the summer of 1900, he probably had a different sort of blue in mind to that which streaked the Edinburgh sky on an icy Sunday afternoon in November. For Donald Runnicles, returning to conduct the BBC Scottish Symphony Orchestra, there was clearly something of the onset of winter in what is normally the sunniest of Mahler symphonies.

Every fan of his fiction knows that Haruki Murakami loves jazz and lets the music play throughout his books. Yet in this 320-page dialogue between the novelist and his equally eminent compatriot, conductor Seiji Ozawa, it’s the veteran maestro of the baton who makes the boldest lateral leap between their shared Japanese culture and the Western forms they admire.

The Philharmonia’s Sunday concert wasn’t quite the event they’d planned. Christoph von Dohnányi scored a hit last season with Schubert's Ninth Symphony, so his reading of the Eighth seemed an ideal way to begin. But Dohnányi withdrew early on, leaving the work in the less inspiring hands of Josep Pons.

Jay C. Batzner: as if to each other… R. Andrew Lee (piano) (Irritable Hedgehog)

What do Boulez's Éclat, for 15 instruments, and Mahler's Seventh Symphony, for over 100, have in common? Most obviously, guitar and mandolin, symbols of a wider interest in unusual sonorities. But while Boulez aims, as often, for needle point precision, Mahler uses selective groups, at least up to his finale when he exuberantly exchanges night for day, to create peculiar and unsettling grades of chiaroscuro.

The mid-way point of the BBC Proms has just passed. Attention during the eight-week season will inevitably tend to gravitate towards the novelties, “events” and one-offs, but one pre-condition for the summer to be going well is that the Proms' backbone ensemble, the BBC Symphony Orchestra, which plays no fewer than 12 of the concerts, has to be on good form. Ideally, they should be playing well across a wide range of repertoire, they should be getting full or nearly full houses, and their relationship with their principal conductor should be positive and productive.

Few 87-year-olds would have the stamina to conduct over 100 minutes of Mahler. Bernard Haitink, though, has always kept a steady, unruffled hand on the interpretative tiller, and if his way with the longest of all the symphonies, the Third, hasn't changed that much since his first recording made half a century ago with his Concertgebouw Orchestra, there's still reassurance in the sheer beauty of the music-making.

After a grey start, there was a spectacular sunset around midnight on the second of my two days in Reykjavik. It's what brings one of Iceland's most brilliant younger-generation talents, pianist Víkingur Ólafsson (and yes, he's worked with Björk), back to his homeland every June. He launched Reykjavík Midsummer Music in 2012, the first full year of programming at Olafur Eliasson's ever amazing Harpa concert halls and conference centre on the harbour.

Aukai Markus Seiber (Aukai Music)

Left, alone, Hans Abrahamsen’s new piano concerto for the left hand, swirls out of the darkness to a jagged motor rhythm. Piano and orchestra clash and interlock; you’re reminded of Prokofiev and Ravel. Then something happens. A piano plays, but the soloist is motionless. It’s been there all the time, of course – an orchestral piano, up on the percussion risers. But now it’s turned threatening: upstaging the soloist with its full two-handed range and stealing his musical voice, his very identity.