This cannot be done with Property Patterns, but you can use a Business Rule for this purpose. You can create a Business Rule that will be launched before creating a user and that will always set the first letter of the user's name in upper case. See the Validate/Modify User Input Using a Script Tutorial for instructions on how to create such a Business Rule. On the 5th step of the tutorial, you need to paste the following script:
$firstName = "%givenName%"
$firstName = "%givenName:upper,1%" + $firstName.Substring(1)
$Context.SetModifiedPropertyValue("givenName", $firstName)
If you would also like to set the first letter of the user's surname in uppercase, add the following lines to the end of the script:
$lastName = "%sn%"
$lastName = "%sn:upper,1%" + $lastName.Substring(1)
$Context.SetModifiedPropertyValue("sn", $lastName)