The short answer is: No.
Orphan pages are pages that reside on your website and are a part of it, but there is no active link pointing to that page. Therefore, your users cannot find them when visiting your site. Crawlers or search engines cannot find them either.
Orphan pages can only be reached by explicitly knowing where it exists on your site, typically by knowing its exact URL.
What can Siteimprove do?
If you know the exact URL of the orphaned page/s, Siteimprove can set up an 'Extra Index URL' to crawl the page/s.
Please submit a Support ticket to have an 'Extra Index URL' set up on your site.