||Here's somethgin from the website of the Hindu Temple in Pittsburgh,http://www.svtemple.org/temple/faq.shtml
The hair offering puja can be done anytime from 9:45 a.m. to 7:00 p.m. during weekdays. During weekends, hair-offering cannot be performed between 10:45 a.m. to 1:30 p.m., because of Abhishekam. At the time of puja, three strands of hair are removed. If full tonsure is required after the puja, you may have to go Tony’s Barber Shop which is 2 miles from the temple. The direction for the shop is available at the temple office. Please note that the barber shop is closed on Sundays and Mondays. The puja charges are $31, and Tony charges about $10. If you need his services on Sunday or Monday, please call him at 412-856-6223 (Shop) or 724-726-5754 for an appointment. He charges $20 on Sundays and Mondays.
No, the tonsure does NOT have to be done in or at a temple, not by a priest, nor by a hindu, nor is it, in and of itself, an act of worship.