-% Define \startlambda \stoplambda
-\definetyping[lambda][option=LAM,style=sans,before=\startboxed,after=\stopboxed,strip=auto]
+% Define \startlambda \stoplambda. Suppress page breaks directly before
+% such a box (\page[no] only works directly after a paragraph break, so
+% insert one).
+\definetyping[lambda][option=LAM,style=sans,before={\par\page[no]\startboxed},after={\stopboxed},strip=auto]