Remove the space between Firstname & Lastname

I am a beginner with opencart 1.5.4.1.
I want to remove the space between Firstname & Lastname of the customer name in orders. Because in Chinese format, we used to simply connect firstname and lastname without space.
For example: Amy Jobs --> AmyJobs.

I tried to find out the code to change it but didn't work....really hope someone can help me.

Thank you so much

Search for 'CONCAT' in ../admin/model/sale/order.php;

eg: CONCAT(o.firstname, ' ', o.lastname)

change to:

CONCAT(o.firstname,o.lastname)

Hello grgr,
Thank you soooo much. That's just what I need!
It changed the name of the order list. But if I click "view" order. In the tab of "order details" still have space.
Could you help me to locate the php file again?

Thanks a lot