Arista Records executive vice president Lionel Ridenour has ankled his post, after a decade with the BMG label, to pursue as-yet-unspecified “new business opportunities.”Arista did not immediately name a successor for Ridenour, but senior VP Steve Bartels is expected to take on at least some of his management duties. Exec worked his way up through the ranks at Arista, starting in 1993 as senior director of R&B promotion and later moving to veepee and eventually senior VP of that department. He was tapped exec VP in July 2000. Along the way, he worked on promotion and marketing campaigns for such Arista acts as Toni Braxton, TLC, Usher, Notorious B.I.G. and Whitney Houston.