(LENOX, Mass.) – Young Spanish conductor Pablo Heras-Casado makes his BSO and Tanglewood debuts Friday, July 22, as he and the orchestra are joined by renowned mezzo-soprano Susan Graham for an all-Baroque program including vocal excerpts from Gluck’s Iphigénie en Tauride and arias from Handel’s Alcina and Ariodonte. Handel’s vocal music forms the heart of…