Convert String into Pascal Case

This method is used for conversion of input string into pascal case

private string ConvertToPascal(string strFileName)
    {
        if (strFileName == null) throw new ArgumentNullException("strException", "Null is not a valid string!");
        if (strFileName.Length == 0) return strFileName;
        string[] strWords = strFileName.Split(' ');
        for (int i = 0; i < strWords.Length; i++)
        {
            if (strWords[i].Length > 0)
            {
                string strWord = strWords[i];
                char strFirstLetter = char.ToUpper(strWord[0]);
                strWords[i] = strFirstLetter + strWord.Substring(1);
            }
        }
        return string.Join(" ", strWords);
    }