What is an electron that occupies the lowest available energy orbital?
It depends on what you mean by lowest available energy orbital.
If you meant an electron that is within the lowest possible energy orbital, then it's a core electron (in which case there is no distinction between excited or ground states unless there is only one occupied energy level).
If you mean the lowest unoccupied molecular orbital (LUMO), then it's an excited valence electron of the molecule, since the LUMO is right above the highest occupied molecular orbital (HOMO).
If you mean the lowest unoccupied atomic orbital, then it's an excited valence electron of the atom, since that orbital is by definition above an occupied orbital. Hence, it must have been promoted via an excitation source such as UV light or heat.