The Arnau (sometimes Arnow) that I am related to are from Menorca. They came to Florida as part of the Turnbull Plantation colony and settled in what is now New Smyrna Beach, Florida and then St. Augustine, Florida. The Turnbull Colony was established in 1764, during the brief period that England held Florida, a few years later it was ceded back to Spain and the Menorcans escaped (it's a long story) to St. Augustine.
Because the settlers were coming from a Catholic background into a Protestant one, a priest, Father Camps, came with them and kept very complete records.
I hope this helps some