Quickcheck: Is it true that Schwarzenegger almost didn't say 'I'll be back!' in The Terminator?

Former governor of California Arnold Schwarzenegger played a time travelling robot assassin sent back from the future to kill the mother of the leader of the human rebellion in the 1984 James Cameron science fiction classic, The Terminator. - filepic

WHENEVER somebody says "I'll be back", it's tough not to associate that phrase with legendary actor Arnold Schwarzenegger.

But is it true that the legendary catchphrase, which originated from The Terminator (1984), almost didn't happen?