For the fourth installment in their “Music in Exile” series, the Toronto-based ARC Ensemble turns its attention to the music of Walter Kaufmann. Despite a promising start in Prague and then Berlin, and friendships with Albert Einstein and with Franz Kafka’s circle, Kaufmann’s career become a casualty of the Nazi regime that forced scores of Jewish musicians to flee Germany. Kaufmann’s intriguing and extensive body of work remains largely forgotten. The hallmark of this remarkable music, explains the ARC Ensemble’s Artistic Director Simon Wynberg, is its striking originality. There are flashes of Debussy, Bartók, and Stravinsky, and hints of klezmer music, but the end result is a world of inventiveness and surprises.