  Anelastic relaxation and $^{139}$La NQR relaxation measurements in
La$_{2-x}$Sr$_x$CuO$_4$ for Sr content x around 2 and 3 percent, are presented
and discussed in terms of spin and lattice excitations and ordering processes.
It is discussed how the phase diagram of La$_{2-x}$Sr$_x$CuO$_4$ at the
boundary between the antiferromagnetic (AF) and the spin-glass phase (x = 0.02)
could be more complicate than previous thought, with a transition to a
quasi-long range ordered state at T = 150 K, as indicated by recent neutron
scattering data. On the other hand, the $^{139}$La NQR spectra are compatible
with a transition to a conventional AF phase around T = 50 K, in agreement with
the phase diagram commonly accepted in the literature. In this case the
relaxation data, with a peak of magnetic origin in the relaxation rate around
150 K at 12 MHz and the anelastic counterparts around 80 K in the kHz range,
yield the first evidence in La$_{1.98}$Sr$_{0.02}$CuO$_4$ of freezing involving
simultaneously lattice and spin excitations. This excitation could correspond
to the motion of charged stripes.
