Archivolts in the plural, of course. This is the closest I can get and I think it's the right term. At least, it's the one they use in the Corpus of Romanesque Sculpture in Britain and Ireland.

First, some pictures, in addition to yours:

arquivolta baquetonada:
"Constan los arquillos de una única arquivolta baquetonada."
http://www.lafronteradelduero.com/Paginas/coruna_del_conde.h...
Picture:
http://www.lafronteradelduero.com/Imagenes/coruna_del_conde/...

"Los ventanales citados tienen aspillera central, un gran derrame exterior para optimizar la entrada de luz al interior del templo y se rodean de una fina arquivolta baquetonada sobre pareja de columnas."
http://www.arteguias.com/iglesia/hermosilla.htm
Picture:
http://www.arteguias.com/iglesia/ventanalhermosilla.jpg

"Two clerestorey windows survive on the E, N and W walls of the N transept. In each case, inside and out, these have en delit shafts with carved capitals carrying a roll archivolt."
http://www.crsbi.ac.uk/site/246/image/feature/2188/

"The arches are round headed and each has a plain roll archivolt."
http://www.crsbi.ac.uk/site/1147/
http://crsbi2-images.cch.kcl.ac.uk/iip/iipsrv.fcgi?FIF=0/055...

"Baquetonada" means with a "baquetón", which is a round moulding:

"Baquetón
Tipo de moldura redonda, en forma de tallo, vertical y normalmente dispuesta en hilera con otras, utilizada especialmente en la arquitectura gótica."
https://es.wikipedia.org/wiki/Moldura#Baquet.C3.B3n

The word is also applied to the round external shafts in a cluster column:
https://es.wikipedia.org/wiki/Polistilo

"Baquetón: Moldura semicilíndrica."
http://www.arteguias.com/diccionario.htm

So is a roll:

"roll: a nearly cylindrical member, comparatively small"
https://books.google.es/books?id=xEHuWo-M6WEC&pg=PA1193&lpg=...