Sub OneLiners()
'In selection, replace Chr(13) with Chr(11) between all
'consecutive one-line paras, if....

Dim oRng
Application.ScreenUpdating = False
Set oRng = ActiveDocument.range
    For Each Para In oRng.Paragraphs
        If Para.range.End >= oRng.End Then Exit Sub
        If Para.range.ParagraphFormat.Alignment = wdAlignParagraphCenter _
            Or Para.range Like "*[0-9]*" Then GoTo nexxt
        If Para.range.ComputeStatistics(wdStatisticLines) = 1 Then
            Do While Para.Next.range.ComputeStatistics(wdStatisticLines) = 1
                Para.range.Characters.Last.text = Chr(11)
            Loop
        End If
nexxt:
    Next
Application.ScreenUpdating = True
Set oRng = Nothing
End Sub