Q. Are there any websites Walsh offers to allow students to check their papers for plagiarism?

We have this guide to help you out with Plagiarism and How to Avoid It.

As for a website where you can upload a paper and then have it checked for plagiarism, I found Grammarly, which checks grammar and plagiarism mistakes.  You can copy and paste your paper into their text box to see their answers. To test it, I put a paragraph from an article in it and it definitely knew it was not original material.  

You may want to contact the Academic Support Center as well if this is a concern for you.