Helena stands where the Arkansas Delta meets the Mississippi, a river town whose name carries chiefly in blues history: King Biscuit Time went out from here on the radio, and Sonny Boy Williamson played it. The Lily Peter Auditorium serves a different music. It is the town's concert hall, and touring opera has reached it — Verdi's Aida among the works staged there. That a production of that size travels to a Delta river town at all says something about how far American touring companies still go.