Hi Colin,
If you are concerned about this situation, I suggest you choose Office 365 to manage DNS records.
For more information, please try to read the following article:
http://office.microsoft.com/en-in/office365-suite-help/i-already-have-a-website-will-it-move-to-office-365-when-i-add-my-domain-HA103881648.aspx
If there is anything unclear, please let me know. I’d like to assist you further.
Thanks,
Dunk