The priest only elevates one host at the consecration and the same one again at the ‘this is the Lamb of God’ but any hosts on the corporal (i.e., as nicole said, all valid matter that he intends to consecrate) are consecrated.
It is best practice that all the hosts to be received at a Mass are consecrated at that Mass. Sometimes they will run out, and then extra hosts would be taken from the tabernacle which had been consecrated at a previous Mass, but ordinarily all the people would receive a host which had just been consecrated.
You may not see the ordinary, non-celebrant’s host until you come forward for communion but they will be there. In certain parishes, only one will be taken up at the offertory and the others brought to the altar by a server, which might explain why you haven’t noticed them before. Next time you’re at Mass, look at what’s in the centre of the altar for the Eucharistic Prayer; you should see at least one ciborium with the other hosts in it.
