How do I address Arabs in a business email?

The emails are addressed to people we have met but have only a passing acquaintance with. Do we use their first name or a title (eg Mr) and their last name?
For instance in sending an email to Haider al-Abadi should I use
Haider
Mr al-Abadi
Mr Abadi

H2018-02-22T19:52:02Z

Favorite Answer

Mr. Al Habadi.

Anonymous2018-01-16T16:55:23Z

Hadji