MJ, this was not the case on all previous iTunes, the Gracenote info was imported with the CD and you could look it up later by clicking Advanced/ Get Track Names. The current Help Center on iTunes still says you can do it... but it shows an Option tab to click which does not appear if the CD is no longer inserted (in which case you cannot actually do it!):
If you don’t see song information
When you insert a CD into your computer, iTunes finds the CD in the Gracenote media database on the Internet and displays the name and other track information for each song. If songs appear as “Track 01,” “Track 02,” and so on, either you aren’t connected to the Internet or iTunes can’t find the CD’s information.
If you’re not connected to the Internet, you can import the songs anyway, and look up the CD information the next time you’re connected.