You must have it--you can't run PSE without it. My guess is that you were looking in the wrong place. The library in question is not hidden, exactly, in 10.7 and 10.8, but it is very hard to find. You have three library folders: system>library, your username>library, and the one at the top level of your hard drive. You want the last one.
The easiest way to get to it is to go to the finder preferences>sidebar, and turn on Hard Disks under Devices:
Then when you open a new finder window, you can click the name of your hard drive in the list on the left side of the window and the right library will show up at the top level of the results on the right.