Plugin does not not load code when not used (which is good) > Elementor

I thought that WordPress plugins, owing to their nature, load on every
single page.

Well it totally depends on what the plugin does. Their are plugins that only do something in the backend, then you will never see any output in the frontend.

Most likely Elementor does a check if any of its functions are being used on the page, before it loads the neccessary scripts and styles.

If you want to be 100% sure, i suggest you ask the developers.