When was Satan
CAST OUT of heaven?
Question: When was Satan cast out of heaven like LIGHTNING and made to FALL to earth?
Answer: One denomination believes God cast out his adversary Satan from heaven in 1914 when WORLD WAR I started! This is, however, clearly not true. Though no doubt a pivotal year in world history, the great tribulation did not start at that time nor did the Second Coming occur. The devil clearly was removed from heaven many years prior to 1914 A.D.
One foundational Bible verse that gives us a time frame for when Satan was cast out of heaven is in the verse you refer to in your question. In Luke 10:18 Jesus stated he personally witnessed this momentous event which occurred with all the quickness and power of lightning. He was literally ejected from God's throne long before what happened in Genesis 1:2 took place.
Satan's revolt took place when he was on the earth. Our Maker states, in Isaiah 14, that he planned to ASCEND to the third heaven where his throne resided (meaning he was not already there!). And what would our Father's adversary DO once he arrived at the very center of all power and authority? He would mount on all-out assault, with his army of demonic followers, to FORCIBLY take control of God's throne so that he could rule everything (Isaiah 14:13 - 14)!
Before his rebellion and sin, Lucifer's position as a powerful covering cherub (a special class of angels), right over the throne of the universe, is confirmed in Ezekiel 28:14 - 15.
While still obedient, God put him on the earth with certain responsibilities. He then, with one third of all the angels that existed, decided to rebel against God (Revelation 12:3 - 4). God tossed Satan from his heavenly abode when he and his angels arrived to attack it, as Jesus witnessed.
It does appear, however, that the devil will once again try to rise up from the earth to attack God's headquarters, only to get thrown down yet again (Revelation 12:7 - 9). 1914 is far too long ago for Lucifer's second attempt, with his twisted helpers known as demons, to try to take control of the entire universe.