The Frankfurt Opera has announced its new season with a line-up of new productions and a number of stars. New Productions  The first new production of the year, Verdi’s “Il Trovatore,” opens on Sept. 10. Elza Van Den Heever and Leah Crocetto lead an all-star cast that also includes Piero Pretti and Alfred Kim in the lead role. David Bösch directs the new production {…}