just restored my macbook pro late 2011 13" running 10.7 off of nothing more than a time machine backup and it worked fine, even with a blank internal. Just remember to format your new drive with disk utility of mac journaled. make sure your external drive is powered and on before you boot, then press option while booting. select time machine, format the new drive, and restore. Simple...

Just restored my macbook pro late 2011 13" running 10.7 off of nothing more than a time machine backup and it worked fine, even with a blank internal.

Remember to format your new drive with disk utility using the mac journaled file system.

Make sure your external drive is powered and on before you boot, then press option while booting.

Select time machine, format the new drive, and restore.

Simple...