uThis question is answered by the IRS: https://www.irs.gov/affordable-care-act/employers/questions-and-answers-on-employer-shared-responsibility-provisions-under-the-affordable-care-act
In general, an ALE makes an offer of coverage to an employee if it provides the employee an effective opportunity to enroll in the coverage (or to decline that coverage) at least once for each plan year. Whether an employee has an effective opportunity to enroll is based on all the relevant facts and circumstances. An ALE offers coverage for a month only if the coverage would be provided for every day of that calendar month.
