Folks, my bad for not seeing this before. They do list their rubric in the second to last bullet point at the bottom: 55% grades, 45% test scores. Another parent (thanks Dana!) remembered that if you don’t meet your attendance criteria, they don’t rank you. If you do, they do.
This is up on ElRo’s website, under admissions information - it’s a PDF at the bottom of the page.
Not all schools post this info. But, again, you absolutely can ask and they should tell you.