Top panel: 1997–2012 OGLE-II, -III and -IV lightcurve data for LHA 115-S 18 with the timings of optical blue- (Massey & Duffy 2001; Torres et al. 2012 and this work) and far-red (Aret et al. 2012 and this work) spectroscopic and X-ray (Antoniou et al. 2009; Bartlett et al., in prep.) observations indicated. The nearest photometric data points to each observation are given by the filled red symbols. Note that the spectrum of Massey & Duffy and the first epoch of Torres et al. were obtained quasi-simultaneously and the date indicated for the first X-ray observation is the midpoint of the period over which observations were made. Photometric errors are smaller than the symbol size plotted. Lower panels: expanded presentation of two sub-sections of the lightcurve (indicated by dotted lines in the upper panel).