It's possible:
* The name is slightly misspelled: Double-check the spelling.
* He works under a different name: Search using alternative spellings or known aliases.
* He's a relatively unknown actor: His work might be limited to smaller projects or regional productions.
To help you find information, could you provide any additional details? For example:
* Any other information about Jonathan Aldridge? (age, location, profession, etc.)
* Any specific projects you might have seen him in? (movie title, TV show name, etc.)
With more information, I might be able to help you find the information you're looking for.