VBA to format bold a concatenated string

Assuming the starting phrase is in A1, the second in A2, and the third in A3,

Private Sub Worksheet_Change(ByVal Target As Range)
    If Not Intersect(Target, Me.Range("A1,A2,A3")) Is Nothing Then
        On Error GoTo Oops
        Application.EnableEvents = False
        With Me.Range("A155")
            .Value = Trim(Me.Range("A1").Text & " " & _
                          Me.Range("A2").Text & " " & _
                          Me.Range("A3").Text)
            .Characters(Start:=Len(Me.Range("A1").Text) + 2, _
                        Length:=Len(Me.Range("A2").Text)).Font.Bold = True
        End With
Oops:
        Application.EnableEvents = True
    End If
End Sub