Sub Demo()
Application.ScreenUpdating = False
Dim Rng As Range, StrYY As String, StrMM As String, StrDD As String
Application.CheckLanguage = True
With Selection
  Set Rng = .Range
  .LanguageID = wdFrenchCanadian
  .NoProofing = False
  With .Range
    With .Find
      .ClearFormatting
      .Replacement.ClearFormatting
      .Text = "<[JFMASOND][a-z.]{2;9} [0-9]{1;2}, [0-9]{2;4}>"
      .Replacement.Text = ""
      .MatchWildcards = True
      .Wrap = wdFindStop
      .Forward = True
      .Format = False
    End With
    Do While .Find.Execute
      If .InRange(Rng) Then
        StrYY = Split(.Text, " ")(2): StrMM = Left(Split(.Text, " ")(0), 3): StrDD = Split(Split(.Text, " ")(1), ",")(0)
        If Len(StrYY) = 2 Then StrYY = "20" & StrYY
         Select Case StrMM
          Case "Jan": StrMM = " janv. "
          Case "Feb": StrMM = " févr. "
          Case "Mar": StrMM = " mars "
          Case "Apr": StrMM = " avr. "
          Case "May": StrMM = " mai "
          Case "Jun": StrMM = " juin "
          Case "Jul": StrMM = " juill. "
          Case "Aug": StrMM = " août "
          Case "Sep": StrMM = " sept. "
          Case "Oct": StrMM = " oct. "
          Case "Nov": StrMM = " nov. "
          Case "Dec": StrMM = " déc. "
        End Select
        .Text = StrDD & StrMM & StrYY
        .Font.Color = 16711937 'Blue HTML 1/1/255
      Else
        Exit Do
      End If
      .Collapse wdCollapseEnd
    Loop
  End With
End With
Application.ScreenUpdating = True
End Sub