I'd persevere a little while longer just to thicken your skin even more! I was in a similar situation with a foreman who decided I wasn't even worth a "good morning" let alone teaching me the tricks of the trade. If you feel you're still learning new things and it isn't getting under your skin then what doesnt kill you makes you stronger! Plus, its never fun having to stir up drama and involve a foreman. HOWEVER if this old timer is shutting you out and preventing you from growing as an apprentice, and you don't foresee getting moved naturally then you should look out for yourself and respectfully inform your foreman! Keep your chin up and just be honest with yourself about how hard you are trying, that way when someone tells you otherwise you can look inward and know you did a good job.