God made Lucifer an anointed cherub. While he had power and rule, God gave the ruler-ship of Earth to Adam and Eve. Could this have upset him and caused resentment to brood? Something further to consider: is it possible that the moment Satan fell was the same moment he was tempting Eve? Because of his apparent victory in leading mankind to submit to his rule and authority instead of the other way around that God had intended, could this have shown power to the angels? Satan was now the ruler of the “rulers” and this may have enticed a third of the angels to turn away from their Creator and follow the creation instead.
We all know that if a leader acquires a major victory of success, many are willing to follow that individual. If Lucifer became Satan either just before or during Eve’s temptation and then went to Heaven and boasted about his accomplishment, this would have influenced many to join him. It then is possible that, while Adam and Eve were sewing fig leaves to cover their shame, war erupted in Heaven. Perhaps just as soon as God threw Satan and his cohorts down to the Earth, He then came down Himself to rescue His beloved children from the domain of darkness. This might then explain why Satan was with Adam and Eve when God found them.