Pianist Yuja Wang sits in with the Cleveland Orchestra tonight at Severance Hall as it performs Rachmaninoff's Fourth Piano Concerto. The program also includes pieces by Prokofiev, Poulenc and Ravel. Case Western Reserve University's Emily Laurance gives the pre-concert talk that begins an hour before the concert. The concert takes place at 8 tonight and tomorrow night and at 3 p.m. on Sunday at Severance Hall. Consult the orchestra website for ticket prices. (Niesel)