At the start of Elgar’s Second Symphony the full orchestra hovers, poised. It pulls back; and then, like a dam breaking, the music surges forward in wave upon wave of golden sound. ‘Rarely, rarely, comest thou, Spirit of Delight!’ writes Elgar, quoting Shelley, at the top of the score, and you won’t hear that spirit captured more exuberantly than in a performance from May 2009 by the Berlin Philharmonic under its future music director Kirill Petrenko.