U.S. Company sponsors medical plan for its U.S. citizen employees work

[Guest PALAWYER]

Help- need to prove to my client (or find out now rather than later if I am wrong) that a welfare plan sponsored by a U.S. corporation to cover U.S. citizen employees who are posted abroad (plan does not cover U.S. based employees) is subject to ERISA. I believe it is- but I can't find any cite for direct support- I need a cite!

Thank you