You can't do this in a sane way for Google search queries.
Why? Google is using HTTPS (SSL) everywhere now. All traffic between the endpoints (browser & Google server) is encrypted and checked for integrity.
The only way to read (let alone modify) encrypted traffic is changing it at or beyond on one of the endpoints. Suggestions in the direction of
mod_rewrite are all server-side and you probably don't have access at Google's servers. ;)
Workarounds for this like modifying your local DNS forwarder to answer differently and set up a proxy server with SSL MITM won't work either without adding your own fake CA to every browser. Moreover, using Google Chrome, it's way harder to circumvent this as Google has hardcoded fingerprint signatures to check. Refer to some news regarding the DigiNotar in 2011, for example here.
Back to your objective and the only endpoint you can control here. My suggestion would be to find a browser addon/plugin that will fit your needs and enforce it for the user. For example by modifying the file system permissions for the configuration of it to prevent the user from changing it and disallow any new software installations.