Harry's scar only starts hurting when he is around Voldemort. Voldemort wasn't alive enough for him to be disturbed early in the books, before he was properly alive. Remember that Harry's scar doesn't start to "ache", until he is in the direct presence of Voldemort. It makes since his scar first hurt when he was in the Presence of Professor Quirrel.
"I met him when I travelled around the world. A foolish young man I
was then, full of ridiculous ideas about good and evil. My master
showed me how wrong I was. There is no good and evil... there is only
power, and those too weak to understand it... Since then, I serve him
faithfully, although I have let him down many times." —Quirinus
Quirrell on Lord Voldemort wikia article Quirinus Quirrell
Voldemort was off doing more "important" things than being around Harry.
And, because I can't summon a quote at the moment.
“I was ripped from my body, I was less than spirit, less than the
meanest ghost . . . but still, I was alive.”
― J.K. Rowling, Harry Potter and the Goblet of Fire goodreads.com
“Some say he died. Codswallop, in my opinion. Dunno if he had enough
human left in him to die. Some say he’s still out there, bidin’ his
time, like, but I don’ believe it.” ― J.K. Rowling, Harry Potter and
the Sorcerer's Stone
He probably wasn't that strong enough. In addition, to being to far away. IIRC, he was at his full strength mostly in the 4th book, since that is indeed when he got his body back.
Also, Voldemort was very far away from Harry. He was at Hogwarts, in a faraway forest, etc. Nowhere near Harry.
You could also say that Harry was protected by his mother's protection and the power of the Privet Drive home, but I don't think so.
This may be slightly off-topic.
Also cosforums.com, they have interesting theories. Its may not be exactly what your looking for, though.