energy - What causes an electron to return from a higher orbit to a lower orbit

Ultraviolet light can cause electrons from Hydrogen gas to jump from a lower energy orbit to a higher energy orbit. What causes the electrons to return from the higher energy orbit to the lower energy orbit by releasing photons? Would it be possible to maintain the electrons in the higher energy orbit? How? Would placing the hydrogen gas in an electric field generated between the parallel plates of a capacitor have this effect?