Implementing a Proper() case function in PL/SQL

I found that I needed to convert some raw column names (i.e. THIS_IS_MY_COLUMN) into a human-readable “Proper” or “Title” case form, e.g. This Is My Column.

Scouring the web, I didn’t find out I could steal, so here’s my implementation:

   function Proper(
      p_string varchar2
   ) return varchar2
   is
      l_string varchar2(200);
      l_proper varchar2(200);   
   begin
      l_proper := '';
      -- change any underscores to spaces:
      l_string := replace(lower(p_string), '_',' ' );

      for i in 1..length(l_string)
      loop
         -- obviously the first character is UPPER:
         if i =1 then
            l_proper := l_proper || upper( substr( l_string, i, 1 ) );
         else
         -- if the character is preceded by a space, UPPER it:
            if substr( l_string, i-1, 1 ) = ' ' then
               l_proper := l_proper || upper( substr( l_string, i, 1 ) );
            else
               l_proper := l_proper || substr( l_string, i, 1 );
            end if;            
         end if;   
      end loop;
      return l_proper;
   end;