The UIApplicationDelegate Protocol application:willChangeStatusBarOrientation:duration:
You can use one of these two methods to see:
- (void)application:(UIApplication *)application willChangeStatusBarOrientation:(UIInterfaceOrientation)newStatusBarOrientation duration:(NSTimeInterval)duration;
- (void)application:(UIApplication *)application didChangeStatusBarOrientation:(UIInterfaceOrientation)oldStatusBarOrientation;
Apple's UIApplicationDelegate Protocol Reference is here: