Joyce DiDonato and Juan Diego Flórez headline Rossini’s bel canto tour-de-force "La Donna del Lago" on Great Performances at the Met (check local listings). Based on the work by Sir Walter Scott, DiDonato is Elena, the lady of the lake pursued by two men, with Flórez as Giacomo, the benevolent king of Scotland. Michele Mariotti conducts debuting Scottish director Paul Curran’s staging.