Rochester's classical music audiences are accustomed to visits from celebrated international guest conductors and soloists. But an entire orchestra stopping by the Eastman Theatre? That's a decidedly uncommon occurrence. This Friday, the Toronto Symphony Orchestra, led by its music director, Peter Oundjian, will perform works by J.S. Bach and Dmitri Shostakovich — two composers RPO fans have not yet heard in the current Philharmonics season. Canadian pianist and Bach specialist Angela Hewitt will join the orchestra for the Baroque composer's Keyboard Concerto No. 1 and No. 5. Originally written for harpsichord, Hewitt will perform these arresting, elegant pieces on the piano. The concert will close with Shostakovich's Symphony No. 8, a grand yet unsettling work in which the elegance is tempered with a sense of menace and dread.