Comparison of the profiles of Ca I 6572.78 Å (solid lines) and Ti I 6556.06 Å (dotted lines) for selected dates, highlighting the stability in radial velocity of the Ti I 6556.06 Å line (top panel). Temporal evolution of the Li I 6707.83 Å line showing a drastic change from a P Cygni-type profile in 2007 to a double-absorption profile and a subsequent weakening of the absorption components (bottom panel). The colour-coding is the same for both panels. To guide the eye, the position of zero radial velocity is given by the grey vertical line.