That is a pretty high pH, as you noticed. I think your temperature is really low for lacto. I shoot for at least 100F, but it can be difficult to keep it at that temp. I usually try to pitch at like 110 or so, and put a bunch of heating pads and sleeping bags around the carboy to hold the temp as warm as possible. I don't worry about letting it go for a week or more, but I also start off with a much higher original gravity.
If you can warm it up, I think it should help. Also, if you haven't seen any signs of fermentation I wouldn't worry too much, because that means there was no weird yeast or other bacteria going to work.