A little off subject, sorry, but I am having a hard time understanding when to apply a contraction. I thought it was when one word ending in a vowel and the next word beginning in a vowel... So J'aime instead of "Je aime", why not "T'aimes" instead of "Tu aimes"?
with the basic pronouns (je,tu,il,elle,nous,vous,ils,elles), only je is ever contracted. The contraction happens when the following verb starts with a vowel.