public void SetName( 
   string name
)

{
  //Note: Must be on QueuedTask.Run

  //Build geometry
  Coordinate2D ll = new Coordinate2D(6, 2.5);
  Coordinate2D ur = new Coordinate2D(8, 4.5);
  Envelope env = EnvelopeBuilderEx.CreateEnvelope(ll, ur);

  //Reference MF, create legend and add to layout
  MapFrame mf = layout.FindElement("Map Frame") as MapFrame;
  var surroundInfo = new LegendInfo()
  {
    MapFrameName = mf.Name
  };

  var legendElm = ElementFactory.Instance.CreateMapSurroundElement(
    layout, env.Center, surroundInfo) as Legend;
  legendElm.SetName("New Legend");
}

{
  //Note: Must be on QueuedTask.Run

  //Build geometry
  Coordinate2D center = new Coordinate2D(7, 5.5);

  //Reference a North Arrow in a style
  StyleProjectItem stylePrjItm = Project.Current.GetItems<StyleProjectItem>()
                                 .FirstOrDefault(item => item.Name == "ArcGIS 2D");
  NorthArrowStyleItem naStyleItm = stylePrjItm.SearchNorthArrows(
                                         "ArcGIS North 10")[0];

  //Reference MF, create north arrow and add to layout 

  var mf = layout.FindElement("Map Frame") as MapFrame;
  var narrow_info = new NorthArrowInfo()
  {
    MapFrameName = mf.Name,
    NorthArrowStyleItem = naStyleItm
  };
  var arrowElm = (NorthArrow)ElementFactory.Instance.CreateMapSurroundElement(
    layout, center.ToMapPoint(), narrow_info) as NorthArrow;
  arrowElm.SetName("New North Arrow");
  arrowElm.SetHeight(1.75);
  arrowElm.SetX(7);
  arrowElm.SetY(6);
}

{
  //Update an element's properties.

  //Note: Must be on QueuedTask.Run
  //Find a single specific element
  element = layout.FindElement("Rectangle") as Element;
  // update an element's name
  element.SetName("New Name");

  // update and element's visibility
  element.SetVisible(true);
}