As an officer with multiple tattoos, please allow me to comment.
Although you are technically correct and a non-offensive sleeve tattoo should not be an issue, I would recommend you wait until you are actually in the CAF before getting such a tattoo. Although the regulations say it's OK, the fact remains that for the most part, tattoos are not as common in the officers' mess as they are elsewhere. At the very least, they may give you a hard time on basic training (watch An Officer and a Gentleman). My general advice for anyone is that tattoos should be able to be covered up when wearing any military order of dress (including the short-sleeve shirt orders). Once you're in the CAF and finished basic training and your position is secure, you can start to let your personality out for others to enjoy, but until that point, it is probably best to conform with the norm. It just makes life easier.