How can I frame some subregion in a Lambert projected map?

Dear All,

I created a Lambert projected map about Europe by the following way:

   axesm('lambert','maplatlimit',[ 26.5861 71.8699],'maplonlimit',[-34.748 60.8422], 'Grid', 'on');
  S = shaperead('landareas','UseGeoCoords',true);
  geoshow([S.Lat],[S.Lon],'color','black');
  pcolorm(lat,lon,z);
  demcmap(z);

I would like to frame some subregion inside the map e.g. British Isles latitude=[50 59] and longitude=[-10 2]. Could someone suggest me a solution? Thank you for your help in advance!