After a galvanic opening concert devoted to contemporary American music, this week's Rochester Philharmonic Orchestra program — with works by Haydn, Mozart, and Dvoák— may seem staid and conventional. But there's some welcome novelty here: the orchestra will be performing Haydn's beautiful Symphony No. 34 for the first time, and Dvoák's very tuneful, very popular Symphony No. 8 makes a welcome RPO return after almost two decades. Separating the two symphonies is Mozart's Piano Concerto No. 17. It's not one of his most familiar concertos, but definitely one of his most elegant and effervescent — the very definition of "rococo." The pianist is Orli Shaham, while conductor David Danzmayr makes his RPO debut.