Neutral hydrogen observations has bee made in the directions of an X-ray flare detected in the Lupus region. The flare position lies within the boundaries of a hole in the HI emission. Several physical parameters are derived and probable interpretations are discussed. The conclusion is that the hole is the result of the ionization produced by two early-type stars: HD 135348 and HD 135764. The first one could be the optical counterpart of the flare.