Answer:
In fact yes.
Although it is pretty obvious lemon is acidic, a weak acid. The response that it creates in the body, however, is extremely alkaline. Lemon and lime juice promote the release of sodium bicarbonate from the pancreas to support enzyme activity. As well as this, lemon is converted to potassium citrate in the intestine which is also alkaline.
So... drink away!!
This is a good PDF to read for further info:
http://askdoctoryung.com/wp-content/uploads/file/Articals%20by%20Renew%20You/CT-080311-01-TX-AT-posted-Get-Your-pH-Right-renew-you.pdf