i have installed an lxml on my mac, when i type in python like this
localhost:lxml-3.0.1 apple$ python Python 2.7.3 (v2.7.3:70274d53c1dd, Apr 9 2012, 20:52:43)
Run the following command to install the lxml package.
pip install lxml --user
should fix the issue. I tested it on MAC OSX 10.7.5, it worked fine.