Elementor and Cloudflare integrate smoothly with each other, although there has been an issue with Rocket Loader in the past.
The issue was caused by Rocket Loader automatically changing the scripts to load asynchronously, which breaks the editor.
If this is causing you a problem, you can solve this by creating rules in Cloudflare:
Leo Elementor Demo work fine with Cloudflare
1. Create new “Page Rules”
2. Setup “Page Rule”