Earlier this month Pulitzer-winning TV critic Howard Rosenberg retired, and now the lead TV writer Brian Lowry is jumping to Variety as a columnist and critic. Lowry gave his notice this morning after not getting the Rosenberg job. The move leaves the L.A. Times Calendar section thin on television knowledge. The paper reportedly went after an outside critic to replace Rosenberg and was turned down. Other TV writers such as Dana Calvo and Paul Brownfield have moved on to other assignments.