diff --git a/changes/bug6506 b/changes/bug6506
new file mode 100644
index 000000000..4c6f4900d
--- /dev/null
+++ b/changes/bug6506
@@ -0,0 +1,4 @@
+  o Minor features (build):
+    - Detect a missing asciidoc, and warn the user about it, during
+      configure, rather than at build time. Fixes issue 6506. Patch
+      from Arlo Breault.
diff --git a/configure.ac b/configure.ac
index 9a5d589b9..1e69ec48d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1468,10 +1468,10 @@ AC_CONFIG_FILES([
         src/config/torrc.sample
 ])
 
-if test x$asciidoc = xtrue && test $ASCIIDOC = "none" ; then
+if test x$asciidoc = xtrue && test "$ASCIIDOC" = "none" ; then
   regular_mans=(doc/tor doc/tor-gencert doc/tor-resolve doc/torify)
   for file in $regular_mans ; do
-    if ! [[ -f $srcdir/$file.1.in ]] || ! [[ -f $srcdir/$file.html.in ]] ; then
+    if ! [[ -f "$srcdir/$file.1.in" ]] || ! [[ -f "$srcdir/$file.html.in" ]] ; then
       echo "==================================";
       echo;
       echo "You need asciidoc installed to be able to build the manpage.";