Die englischsprachige Wikipedia weiß Folgendes:

"The author adopted the name "Voltaire" in 1718, following his incarceration at the Bastille. (...) t is an anagram of AROVET LI, the Latinized spelling of his surname, Arouet, and the initial letters of le jeune ("the young").[19]

According to a family tradition among the descendants of his sister, he was known as le petit volontaire ("determined little thing") as a child, and he resurrected a variant of the name in his adult life.[20]

The name also https://en.wikipedia.org/wiki/Verlan" target="_blank">reverses the syllables of Airvault, his family's home town in the Poitou region.[21]"

Also:

1. Arovet le jeune -> abgekürzt und latinisiert: AROVET L I -> Buchstaben umgestellt: VOLTAIRE

2. Le petit volontaire -> Voltaire

3. Airvault -> Vaultair -> Voltaire