Should there be a comma after “March 5” in both examples below? I say no. On March 5 at 10 a.m., cops arrested the suspect. On Thursday, March 5 at 10 a.m., cops arrested the suspect. But, I believe the commas are correct in both examples below: On March 5, 2011, at 10 a.m., cops arrested the suspect. OnThursday, March 5, 2011, at 10 a.m., cops arrested the suspect. Thank you.
The easy part's the space required twixt On and Thursday. That aside, all examples look and 'feel' right to me. I wouldn't expect to be corrected if I wrote them that way.