That was one of the initial ideas Tolkien had, and that also made its way into final Silmarillion edition after his death. However, there are notes from later years where its shown he has changed his mind about Orcs elven origin. Also, due to his Catholic upbringing he had struggled with the idea of an intelligent race so corrupted to be irredeemably evil and undeserving of mercy.

In later material the Orcs had been either former humans tortured and deformed by Morgoth/Sauron, or, even later on, automatons possessed by fallen spirits and/or imbued with Morgoths evil will (as only Eru was capable of creating true life, so technically the Orcs would not be real living beings), thus skirting around the intelligent being issue.

Of cource, the Silmarillion does not reflect that, as the released book is based on older material, so in the end, the elven origin of Orcs IS sort of canon, at least as much as anything is, with JRRT constantly changing things.