What about illuminated objects? The same basic mechanisms apply, but the energy that excites the atoms of an illuminated object is actually other light waves! A photon of light is absorbed by an atom, the electron is elevated to a higher energy level, then it drops to it original state, and a photon is released. This photon may or may not be of the same frequency that the atom first absorbed.
Looking at the bigger picture, reflected light can also be depicted in another manner. Light can be thought of as a series of rays. When it strikes an object, each ray is reflected off the object in many different directions. Those that reach our eyes allow us to "see" the object in question.