The high point of this week in classical music is surely the Lieder recital by the superlative German baritone Christian Gerhaher and his regular pianist collaborator, Gerold Huber, sponsored by the Vocal Arts Society at the Embassy of Austria (October 11, 7:30 p.m.). Gerhaher’s most recent Lieder recording is a knockout, and his program for Thursday night is devoted entirely to songs by Robert Schumann. THE SYMPHONY: >> Riccardo Chailly brings his La Scala Philharmonic…