You could use a regular expression to do this:
void Main()
{
var regex = new Regex(@"(January|February|March|April|May|June|July|August|September|October|November|December) \d{2}, \d{4}");
string test1 = "Lorem Ipsum February 01, 2012";
string test2 = "Lorem Ipsum Badmonth 01, 2012";
regex.Match(test1).Dump();
regex.Match(test2).Dump();
}
if you want the search to be case insensitive (will work with February or february) replace it with:
var regex = new Regex(@"(January|February|March|April|May|June|July|August|September|October|November|December) \d{2}, \d{4}", RegexOptions.IgnoreCase);
or (they exactly do the same thing)
var regex = new Regex(@"(?i)(January|February|March|April|May|June|July|August|September|October|November|December) \d{2}, \d{4}");