It is perhaps a little better to think of the photon as interacting with
the atom, rather than the elctron. The "how does the electron know"
question implies the view of an electgron as a point particle that
begins travelling to a higher orbit (like a planet getting kicked), and
how does it know the end point of the trip. But that view is just not
tenable.
The atom is in an energy state, it has other possible states. If the
right amouint of energy is available, a transition can take place. If
the energy of the photon does not correspond to an energy transition of
the atom, and is insufficient to remove an electron from the atom, the
electron will either scatter off the atom or simply pass through
unaffected.
Jerry Epstein