Extension method to truncate a string to the last space after a specified length

StringExtension.cs

public static class StringExtension
  {
     public static string SplitByCaps(this string value)
        {
            var r = new Regex(@"
                (?<=[A-Z])(?=[A-Z][a-z]) |
                 (?<=[^A-Z])(?=[A-Z]) |
                 (?<=[A-Za-z])(?=[^A-Za-z])", RegexOptions.IgnorePatternWhitespace);

            return r.Replace(value, " ");
        }
        
      public static string ToTitleCase(this string value) {
          return System.Threading.Thread.CurrentThread.CurrentCulture.TextInfo.ToTitleCase(value.ToLower());
      }
        
    public static string TruncateToLastSpace(this string valueToTruncate, int maxLength)
        {
            if (valueToTruncate == null)
            {
                return string.Empty;
            }

            if (valueToTruncate.Length <= maxLength)
            {
                return valueToTruncate;
            }

            string retValue = valueToTruncate;

            int lastSpaceIndex = retValue.LastIndexOf(" ",
                                                      maxLength, StringComparison.CurrentCultureIgnoreCase);

            if (lastSpaceIndex > -1)
            {
                retValue = retValue.Remove(lastSpaceIndex);
            }

            if (retValue.Length < valueToTruncate.Length)
            {
                retValue += "&hellip;";
            }
         
            return retValue;
        }
}