June 4 (Reuters) - Canada’s main stock index rose at open on Friday, driven by gains in energy and gold stocks as underlying commodity prices gained, while more-than-expected jobs were lost in May due to the impact of COVID-19 lockdowns. * At 09:31 a.m. ET (13:31 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was up 108.06 points, or 0.54%, at 20,049.45. Reporting by Shivani Kumaresan in Bengaluru; Editing by Vinay Dwivedi Our Standards: The Thomson Reuters Trust Principles.