On Friday, March 1, at 7 p.m., organist John Walthausen will test the limits of Christ Church’s new C.B. Fisk pipe organ in a free First Friday concert. A rising star on the international scene, Walthausen offers an exciting program of early and contemporary music with works by John Bull, Dietrich Buxtehude, Benoît Mernier, Vincent Paulet, and Grégoire Rolland.