What does Nokia boss Stephen Elop need to do this year? The ailing mobile giant he leads ended 2012 surprisingly strongly. But the market remains understandably wary. To convince sceptics, Mr. Elop’s biggest task is ensuring top-end smartphone sales really take off. The strategy for cheaper phones may need a rethink. Floating Nokia Siemens Networks (NSN), the revamped network-equipment unit, would help too.