@valk to answer to your question regarding the “liaison” happening with h sometimes, and sometimes not…
I found another interesting website elaborating on this matter: c’est par ici !
Why do we say “les (z)horloges” but not “les (z)héros”?
Both begin by an h, but one is a silent h and the other is a sucked one.
the letter h is sucked when the subject’s article can be “le” or “la”
→ we do not pronounce the “liason” in the plural
The letter h is silent in the other cases. The subject’s article can be l’
→ l’hôpital, l’horloge
in the plural form we do the “liaison” and pronounce
→ les (z)hôpitaux, les (z)horloges
A few words begining by a sucked h:
haïr (to hate)
haleter (to gasp)
hasard (hazard, chance)
hauban (shroud, part of a sailboat)
hautbois (oboe, music instrument)
huis clos (behind closed doors)
hanneton (cockchafer, may-bug)
hurler (to scream, to shout, to yell, to squeal…)
hère (male deer 6 months old or more)
hussard (hussar, light cavalry of any of several European armies in the past, mostly known in Hungary)
harceler (to harass)
hardi (outspoken, bold, fearless)
hure (boar’s head)